This invention relates to a group of novel fluorine-containing aromatic bismaleamic acids (bismaleinamic acids), aromatic bismaleimides (bismaleinimides) derived from the bismaleamic acids and thermosetting resin compositions of addition polymerization type using the bismaleimides. The resin compositions provide solid imide resins excellent in heat resistance and moisture resistance and low in dielectric constant and will have wide uses in electric and electronic devices, optical devices, machine parts, etc.
Polyimide resins obtained by addition polymerization of a bismaleimide are generally excellent in heat resistance and have good electrical and mechanical characteristics. Accordingly polyimide resins of this type have been used as industrial materials in electronic devices and various machines.
However, conventional polyimide resins of the addition polymerization type are relatively high in moisture absorption and moisture permeability and, by absorption of moisture, suffer from lowering of dimensional stability and/or adhesive power. Therefore, when the resins are used, for example, as sealants in integrated circuits or as substrates of printed circuits there are doubts about longterm reliability of the devices. From another aspect, it is not seldom that thermosetting resins for use in electronic devices are required to be low in dielectric constant, but most of conventional imide resins of the addition polymerization type do not meet this requirement.